Tektronix, Inc.

Laudie J Doubrava

John J Pickerd

William A Hagerup

Josiah A Bartlett

Jim L Martin

Dennis Keldsen

System and methods may allow an operator of a signal measurement instrument to characterize and calibrate a network with unsupported connector types, e.g., not traceable to known standards. Adapters having supported and unsupported interfaces can be used to measure the system responses of networks in a system under test. These measurements can be mathematically cascaded to deduce virtual models that produce an accurate and fully calibrated total system response.

Virtual model adapter removal and substitution technique for cascaded networks

A new methodology for the measurement of the S-parameters of a high impedance probe allows obtaining a full two port S-parameter set for the high impedance probe. The measured probe S-parameters are then used for characterization of probes. An alternative method characterizes half of the fixture and termination as a one-port network and expanding it into a two-port error box. The two-port error box is then cascaded with the probe input.

Calibrated S-parameter measurements of a high impedance probe

A system, apparatus and method for performing differential return loss measurements and other measurements as a function of frequency uses a digital storage oscilloscope (DSO) having spectral analysis functions. A waveform generator generates a differential test signal in the form of a series of pulses where each pulse includes spectral components associated with each of a plurality of frequencies of interest. A test fixture presents the differential test waveform to a load including at least one of a device under test (DUT), a short circuit, an open circuit and a balanced load. A signal acquisition device differentially measures the test waveform during each of the load conditions. The signal acquisition device computes an error correction parameter using measurements made during the short circuit, open circuit and balanced load conditions. The correction parameter tends to offset signal acquisition errors within measurements made during the DUT load condition.

Oscilloscope based return loss analyzer

A coaxial cable 24 has an outer conductor 74 surrounding an inner conductor 70. A portion 76 of the inner conductor 70 is stripped of insulation and extends beyond the end of the outer conductor at a cable end 30. A circuit board 12 has a major surface and defines an elongated slot 34. A connection end of the slot is defined by a stop portion of the board 36, and a conductive pad 60 is provided on the board surface adjacent the stop portion at the end of the slot. The stripped portion 76 of inner conductor 70 is connected to the conductive pad 60, and at least a portion of the outer conductor 74 is received in the slot, and may be connected to another contact on the board. The stop portion of the slot is defined as a peninsular connection tab 54 by an elongated hole 50 formed on each side of said stop portion 36 of said slot. The distance between the sides of the conductive pad 60 and the near edges of the elongated holes 50 is selected to provide a predetermined transition impedance.

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Tigard, OR, United States of America

Laudie J Doubrava